TABLE 7.

S. aureus (n = 11) and S. epidermidis (n = 3) strains for which the resistance genotype was discordant with the resistance phenotype

Group and straina	Profile	MIC (μg/ml)	MIC after selectionb (μg/ml)
Group 1
S. aureus R632	mecA, Oxas	2	>64
S. epidermidis R588	mecA, Oxas	0.125	>64
S. epidermidis 184	mecA, Oxas	1	>64
S. epidermidis 3348	mecA, Oxas	0.25	>64
S. aureus ATCC 29213	mecA negative, Oxas	0.5	0.5
S. aureus 18	ermC, Erys	1	>64
S. aureus 75	ermC, Erys	1	>64
S. aureus 93	ermC, Erys	1	>64
S. aureus 5919	ermC, Erys	1	>64
S. aureus ATCC 29213	ermC negative, Erys	0.5	0.5
Group 2
S. aureus R572	mecA negative, Oxar	8
S. aureus R620	mecA negative, Oxar	4
S. aureus R626	mecA negative, Oxar	8
S. aureus R627	mecA negative, Oxar	4
S. aureus MA-5091	ermABC negative, msrA negative, Eryr	>32
S. aureus R566	ermABC negative, msrA negative, Eryr	>32

^aGroup 1, resistance gene present, susceptible; group 2, resistance gene absent, resistant. MIC column data for group 1 strains are the initial MICs. 

^bThe selection of resistant cells was done by plating on media with increasing gradients of the target antibiotic.